On April Fools' Day 1946 at 7:00a.m., the ocean along the coast of Hilo and Laupahoehoe, Hawaii, began to recede in a way no one had seen before. Within minutes a rushing wave of water arrived, and then two more, each more powerful than the previous. Children who had been curious and were gathering up exposed sea creatures from the sand were washed away. In all 149 Hawaiian people were killed by the tsunami. There was no warning. As a result, the Pacific Tsunami Warning System was initiated, and by 1949, was functioning. This book tells the story of the tsunami in the schoolyard and gives factual information about tsunamis in general (in Q & A sidebar format) and the subsequent improvements in detecting and predicting tsunamis around the world. Photos from the Pacific Tsunami Museum and other archives are available.